Evidence-based medicine
Diagnosis of Carpal Tunnel Syndrome

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The Patient

A 44-year-old, healthy woman reports gradually worsening numbness in both hands for several months. The numbness is intermittent and involves her entire hand. It is worse at night and wakes her. She shakes her hands for relief. She also gets numb when driving and holding a telephone. She has no history of neck injury or pain and has no problems with her legs or feet. On examination there is no wasting, deformity, or swelling. Both the provocative pressure test and Phalen's test cause numbness

The Question

Does this patient have carpal tunnel syndrome (CTS; idiopathic median neuropathy at the carpal tunnel)?

Current Opinion

The role of electrodiagnostic testing as a reference standard for the diagnosis of CTS is debated. The lack of a consensus reference standard for the diagnosis of CTS makes it difficult to apply the traditional methods of diagnostic test research. In the absence of a reference standard, some have suggested that we move away from a dichotomous diagnosis (present or absent) and begin to consider diagnosis in terms of the probability of disease.

The concept of probabilities of disease is already

Symptoms

Numbness, not pain, is the predominant symptom in CTS. Exacerbation at night is typical.6, 7 In a study comparing clinical features of patients with the results of electrodiagnostic studies, Katz et al. found that 77% of those with a positive electrodiagnostic test have nocturnal symptoms.3 Graham et al. included nocturnal numbness in his 6-item diagnostic instrument.4, 5 The “flick sign”8 (shaking of the hand to relieve numbness) was 74% specific for CTS in a study that used electrodiagnostic

Shortcomings of the Evidence

Scientific evaluation of diagnostic tests for CTS is usually performed by comparing symptomatic patients with abnormal electrodiagnostic tests to patients with no symptoms and normal tests. The failure to study a population of patients who have a spectrum of disease representative of the clinical population to whom the test might be applied can lead to overestimating the qualities of the test being evaluated. This is referred to as spectrum bias.12

A major problem in the diagnosis of idiopathic

The Future

We need to either agree on a reference standard for the diagnosis of CTS or change from our current mindset of a dichotomous, all-or-none diagnosis (CTS or no CTS) to a mindset that considers probabilities of disease. The tools of clinical research such as the hand diagram and the CTS 6 may be used to form a baseline probability of CTS (an approach that, in a sense, formalizes and quantifies the heuristics that doctors use in day-to-day practice). Diagnostic tests can then be studied in terms

My Current Concepts

The patient described presents with classic symptoms and signs of CTS. The probability of CTS is high and my management would not change based on electrodiagnostic testing.

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References (17)

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Cited by (12)

  • Endoscopic Release Superficial Rather Than Deep to the Transverse Carpal Ligament for Carpal Tunnel Syndrome Improves Immediate Postoperative Transient Symptomatic Exacerbation With Fewer Absences From Work

    2023, Arthroscopy - Journal of Arthroscopic and Related Surgery
    Citation Excerpt :

    From January 2012 to January 2018, 224 patients with CTS were selected and examined at our hospital. Our eligibility criteria for ERSTCL group were as follows: (1) patients between 20 and 59 years of age; (2) a confirmed diagnosis of CTS based on Evidence for Surgical Treatment issued by the British Society for Surgery of the Hand18; (3) idiopathic CTS with symptoms that have lasted for at least 2 months or inadequate responses to the nonsurgical treatments ≥3 months; (4) moderate-to-severe symptoms based on the Levine–Katz Questionnaire (1 = best to 5 = worst)19; and (5) normal contralateral hand as the baseline. Our exclusion criteria were as follows: (1) mild symptoms; (2) bilateral CTS lacking a comparison; (3) a combined or multiple nerve compression; (4) inflammatory neuropathy caused by infection, gout, diabetes, or chronic renal failure; (5) patients who refused to attend the study; (6) revision CTR; and (7) incomplete or interrupted follow-up (Fig 2).

  • Median Nerve and Neuropathy

    2014, Encyclopedia of the Neurological Sciences
  • Revision carpal tunnel surgery: A 10-year review of intraoperative findings and outcomes

    2013, Journal of Hand Surgery
    Citation Excerpt :

    In effect, pain was a major problem in most patients undergoing secondary CTR, with one quarter to one third of patients taking regular medications for neurogenic hand pain. This is in contrast to primary CTS, in which numbness rather than pain is the predominant feature.34 Our intraoperative findings reflect those of previous reports.12,13,16

  • Accuracy of in-office nerve conduction studies for median neuropathy: A meta-analysis

    2011, Journal of Hand Surgery
    Citation Excerpt :

    In light of variation in diagnostic characteristics, physicians using in-office (or laboratory) NCS should adapt test data to the clinical situation. In practice, this is achieved by interpreting the test results with consideration for the pretest probability of disease rather than in absolute terms.42 In particular, a positive test in a patient without clinical evidence of CTS may indicate subclinical disease or a false positive.

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